The subject invention relates to radio frequency communications and more particularly to a system employing plural transmitters, receivers and antennas for use in spacecraft applications. The subject invention is particularly concerned with systems handling S-band and higher frequencies.
As space probes travel to more and more distant reaches of space such as Jupiter and Saturn, the demands on their communication systems become increasingly critical. Power and loss requirements and the need for fail-safe operation increase in the face of demanding environmental and size constraints. For example, it becomes necessary to specify that each component carrying transmitter output power be capable of operation at any pressure without breakdown at power levels up to 120 watts. Filter rejection specifications become increasingly critical, extending out to frequencies in the area of 35 GHz.
Conventionally, RF system elements which function as diplexers, receivers and transmitters are known, for example as illustrated in Wilkinson, U.S. Pat. No. 3,742,506. It is also known to utilize a low gain antenna pointing in all directions to reinstitute communications lost between a high gain antenna and a source. Conventionally, RF filters are constructed of coaxial segments which vary in both length and diameter.
The prior art has not provided a space communication system providing redundant receivers and transmitters capable of servicing either a high gain or a low gain antenna and capable of meeting demanding specifications necessary to operate in the area of Jupiter and Saturn. Conventional filter approaches are incapable of achieving the rejection, loss and power handling requirements necessary in such a system while still being small, light and capable of withstanding the environments experienced in spacecraft applications.